The 1967 film Guess Who's Coming to Dinner by director Stanley Kramer broke ground on racial issues. Mike O'Sullivan spoke with the late director's wife about the impact of the film, newly re-released on a 40th anniversary DVD.

In 1967, 16 states still had laws against interracial marriage, but attitudes were changing. In July of that year, the U.S. Supreme Court overturned those state laws. In December 1967, a classic movie that looked at an interracial relationship was released in Los Angeles - Guess Who's Coming to Dinner.

The film came close to not being made, says Karen Kramer, who worked with her late husband Stanley behind the scenes on the movie.

The story concerned a young African-American doctor, played by Poitier, who wants to marry Houghton, a young white woman. They have not known each other long, but he is an ideal prospect, respected in his field and well mannered. But parents Hepburn and Tracy must deal with the fact he is black at a time when interracial marriages were frowned on.

Poitier's character's parents are also opposed to the marriage. In one scene, the doctor's father tries to dissuade him: "Have you thought what people would say about you? Why, in 16 or 17 states, you would be breaking the law. You would be criminals. And say they changed the law, that don't change the way people feel about this thing."

Karen Kramer says at the time, the topic was sensitive and the director did not tell the studio what the story was about as the film was being made. "He knew that if Columbia pictures knew what the subject matter was, they probably would not have allowed him to make it. So they kept asking him, 'Stanley, what is this film about?' 'Well, it is a love story, he would say. Well, it is a love story."

They started filming in San Francisco. "We had a week up in San Francisco to shoot all the exterior shots, and then everything was really shot right here in Los Angeles at the old Columbia Pictures. But when we were in San Francisco, the studio demanded to see the screenplay. And once they read it, they canceled the film," she said.

The studio said it was canceling the film because star Spencer Tracy was in failing health, and if anything happened to him, they would lose their investment.

"We all came home, and Stanley was devastated. He did not know what to do. But he suddenly got an idea. He grabbed me by the hand. He put me in the car, and we rode over to see Katharine Hepburn. And he said, 'Kate, look, you and I both know this is not the reason why they are canceling this film. It is subject matter," she said.

Kramer and Hepburn put their salaries up for collateral and ensured the film was finished.

It opened quietly at a small theater in Los Angeles.

"And the minute the doors opened, there were lines around the block. I do not mean two blocks. I mean 15 blocks long. And the people just never stopped coming. And it still remains today as one of the highest grossing films of all time for Columbia Pictures," she said.

Some critics loved the film, while others did not, one calling it sanctimonious drivel. Some viewers were outraged by an interracial kiss.

But attitudes were changing, like the changing attitude of Katharine Hepburn in the film, as she talked with Spencer Tracy about their love-struck daughter.

HEPBURN: "Until today, I would never have believed that I could say such a thing, but when she fights you, I am going to be on her side."

Karen Kramer says young people, in particular, responded well to the film when it previewed at Stanford University and after it opened.

Spencer Tracy died just weeks after filming was completed, leaving behind a body of work of nearly 80 films, and Guess Who's Coming to Dinner is an important part of his legacy. Hepburn won the Academy Award for Best Actress in a Leading Role for her work in the film, one of four Best-Actress Oscars she won in her career.

The American Film Institute has included Guess Who's Coming to Dinner among the top 100 films of the 20th century.

The anniversary release is included in a new DVD set with four other Kramer films, including another classic, The Wild One, with Marlon Brando.